UBUNTU: [Config]: Set PANIC_TIMEOUT=10 on ppc64el

UBUNTU: [Config]: Set PANIC_TIMEOUT=10 on ppc64el

BugLink: https://bugs.launchpad.net/bugs/1730660
When stopping CPUS fail when doing kdump, the system will hang
indefinitively, instead of rebooting. Using the default value of 10 for
PANIC_TIMEOUT that we had for trusty allows the system to reboot.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Colin King <colin.king@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>